I've noticed during my playthroughs that when I manage to recruit a drake, the game becomes 2X easier. As the drake is as powerful as a mid-game full stack army, and can be used to defend a choke point, or rampage across the enemy towns.
However, lesser serpents (i forgot what they are called, they are elemental), aren't nearly as useful as the Drake, but is far more balanced.
So here is what I propose.
When one recruits a drake, It starts out as level 1. A baby drake with weak stats. 5 attack, 1 defense, 10 health (or so)
It then "feeds" upon the fallen after each battle it takes part of in the form of experience. It grows in strength(stats), as well as in size. Until it reaches a full adult of level 8-10.
Per each level of the drake, the drake consumes(maintenance) food from the nearest town. i.e. @ lvl 8, the nearest town suffers -8 food.
This not only make the drake more of an rpg/pet type creature, but also will not make it overpowered early-mid game.
As for the glowing snake things, why not have them align to whatever you have most in terms of shards? If we have 5 fireshards, have their strength be adjusted accordingly, as well as morph into the fire ones.
Finally, there are the mercenaries. Never have I seen a more useless set of troops. I mean the darklings that you recruit can steam roll over them.
I propose the ability for the player to fund the mercenary camps(give money), in order for their troop quality to improve.
Thanks